Research objectives and content
The main goal of the research project is the application of spin-coupled valence bond (SCVB) theory to: (i) The description and understanding of the electronic structure of radicals, and (ii) The study of mechanistical aspects in I ,3-dipolar cycloadditions.
(i) There are certain radicals which due to their open-shell electronic structure, are subjected to Jahn-Teller distortions. The detection of conjugated cyclic radicals is difficult, and only the cyclopentadienyl radical (C5H5)- has been detected and spectroscopicaly characterised. It is our goal to perform a thorough study of the electronic properties of the cyclic radicals (C2n+1H2n+1), with n=1,2,3, and assess their Jahn-Teller distortions, using modern valence bond theory.
(ii) The electronic structure of the chemical species known as 1,3-dipoles and the characterisation of their cycloadditions are subjects which are still hotly debated within the scientific community. Molecular orbital theory treatments do not give a clear rationalisation of the bonding involved in these molecules. It is nowadays accepted that 1,3-dipolar cycloadditions may occur by either concerted or stepwise mechanisms, but there is no answer on why either mechanism is preferred. Modern valence bond theory with its ready visual interpretation has great promise for solving this and related problems.
Training content (objective, benefit and expected impact)
The work plan and methods to be used in Bristol comprise using the codes developed by Dr. Gerratt's group, which are able to perform modern valence bond electronic structure calculations on small and medium-sized systems. Visits to collaborators in the group ( Dr. Cooper in Liverpool -UK-, Prof. Raimondi in Milano -Italy-, and Dr. Karadakov in Surrey -UK-) will be useful in order to get acquainted with different aspects in applications of modern valence bond theory. The training at Dr. Gerratt's group will be invaluable especially taking into account that no one in Spain works with spin-coupled theory (the modern version of valence bond theory). As for the results of the project, we expect fundamental advances in the understanding of mechanistical apects of chemical reactions and innovative insights into the electronic structure of radicals.